The present invention relates generally to the field of underground utility and object detection, and, more particularly, to one or more of detecting buried utility and subsurface objects, mapping such utilities and objects, and electronically distributing mapping data to subscribing users.
Various techniques have been developed to locate and map underground utilities and other manmade subsurface structures. Present utility mapping practices take two basic forms: active systems that must have some type of connection to the utility at some accessible point along its path, and passive systems that attempt to map utilities independent of any connection or even prior knowledge of their existence.
Active systems are problematic for various reasons, such as the difficulty and cost of physically accessing the utility and difficulty in sensing non-conductive utilities. Passive systems currently in use often employ GPR. GPR surveys are conducted from the surface, and the location and relative depth to potential utilities are determined from an analysis of reflected energy.
GPR, in general, is a very good sensor for utility mapping purposes, in that GPR is easy to use and provides excellent resolution. However, GPR has problems detecting utilities in certain soil types and conditions that limit GPR""s use in many areas of the United States and the world, such as much of southwest United States (e.g., Arizona). Improvements in GPR sensor design can help overcome some aspects of these inherent limitations, but in many geographic areas, GPR should not be solely relied on due to imaging reliability and accuracy concerns.
Before trenching, boring, or otherwise engaging in invasive subsurface activity to install or access utilities, it is imperative to know the location of any existing utilities and/or obstructions in order to assist in trenching or boring operations and minimize safety risks. Currently, utilities that are installed or otherwise discovered during installation may have their corresponding physical locations manually recorded in order to facilitate future installations. One such system is referred to as the One-Call system, where an inquiry call can be made to obtain utility location information from an organization that manually records utility location information, when and if it is provided. However, the One-Call system is not particularly reliable, as only a certain percentage of the utilities are recorded, and those that are recorded may have suspect or imprecise location data. As such, currently-existing location data for buried utilities is incomplete and often questionable in terms of reliability.
There is a need in the utility installation and locating industries to increase the accuracy of buried utility/object detection. There exits a further need to collect, maintain, and disseminate utility location data of increased accuracy. The present invention fulfills these and other needs, and provides additional advantages over the prior art.
The present invention is directed to improved systems and methods of detecting underground utilities and other subsurface objects. The present invention is also directed to systems and methods of mapping underground utilities. Embodiments of the present invention are also directed to systems and methods of acquiring and storing mapping data in a database. Embodiments of the present invention are further directed to systems and methods of providing access to and use of stored mapping data by subscribing users. These and other features disclosed and claimed herein may be employed individually or in various combinations in accordance with the principles of the present invention.
In one embodiment, a method of detecting one or more underground utilities involves concurrently sensing a number of physical parameters of a subsurface, storing data associated with the sensed physical parameters, and detecting the utilities within the subsurface using the stored data. Detecting the utilities may involve associating stored data for each of the sensed physical parameters in terms of depth and position.
Detecting the utilities may also involve combining the stored data to produce combined data, and detecting the utilities within the subsurface using the combined data. The stored data may be combined to produce combined data expressed in terms of subsurface depth. The stored data may also be combined to produce combined data expressed in terms of horizontal path length. Also, the stored data may be combined based on soil characteristics to produce combined data. The utilities within the subsurface can be detected using one or more of these combined data types.
Detecting one or more underground utilities may also involve determining one or more soil characteristics using one or more of the sensed physical parameters. For example, one or more of soil resistivity, conductivity, permittivity, temperature, water saturation, composition, and hardness may be determined using one or more of the sensed physical parameters.
Detecting underground utilities may involve weighting the stored data based on signal noise associated with the sensed physical parameters, The utilities within the subsurface can be detected using the weighted stored data. Detecting the utilities may further involve fusing the stored data to produce fused data. The utilities within the subsurface can be detected using the fused data.
Tolerance factor data associated with the stored data may further be computed. The tolerance factor data may be computed dynamically or subsequent to storing the data. Weighting the stored data may be accomplished using the tolerance factor data. Tolerance factor data may be computed for each data point of the stored data. Tolerance factor data may also be computed for each of the detected utilities in toto. Ground truth data may be processed to enhance the accuracy of the utility detection result.
Detecting underground utilities may further involve generating a map of the detected utilities. Data associated with the map may be incorporated within a Geographic Information System or other geographic reference system. A 2-D map or a 3-D map of the detected utilities can be generated. Data associated with one or more of the sensed physical parameters or one or more of the detected utilities may be displayed, such as by use of an operator interface.
According to another embodiment of the present invention, detecting one or more underground utilities involves generating radar waves and seismic waves of about the same wavelength. A number of physical parameters of a subsurface are concurrently sensed using the radar waves and seismic waves. Data associated with the sensed physical parameters are stored, and the utilities within the subsurface are detected using the stored data.
The seismic waves, in one embodiment, comprise seismic shear waves. In one embodiment, the seismic shear waves have frequencies of less than 1,000 Hz. In another embodiment, the seismic shear waves have frequencies in excess of 1,000 Hz. For example, the seismic shear waves may have frequencies in the range of about 2,000 Hz to about 3,200 Hz. In another approach, the seismic shear waves may have frequencies of at least about 3 kHz.
The radar waves and seismic waves typically have wavelengths for detecting underground utilities of a predefined size. By way of non-limiting example, the radar waves and seismic waves may have wavelengths for detecting underground utilities having a dimension of at least xe2x85x9c-inch. The radar waves and seismic waves may, for example, have wavelengths of about 3 inches. In general, the radar waves and seismic waves preferably have wavelengths that can facilitate detection of underground utilities at depths of up to about 50 feet, preferably by use of both wave types, but at least by use of one of the waves types for deeper target utilities. For example, the radar waves and seismic waves may have wavelengths of less than about 0.5 feet for conducting near surface (e.g., 15-30 feet or less) underground utility detection. It is understood that the principles of the present invention may be applied for detection of utilities at depths in excess of 50 feet depending on the detection capabilities of the detectors employed. The detection methodology may further involve determining velocities of the radar waves and seismic waves, respectively.
In accordance with a further embodiment of the present invention, detecting one or more underground utilities involves concurrently sensing a number of physical parameters of a subsurface, storing data associated with the sensed physical parameters, and mapping the utilities within the subsurface as a function of subsurface depth using the stored data. The utilities are typically mapped within the subsurface as a function of position and subsurface depth.
Mapping the utilities typically involves computing depth of the utilities as a function of position. Mapping the utilities may further involve computing a depth tolerance factor associated with at least some of the sensed physical parameters. The depth tolerance factors are typically computed as a function of position. Tolerance factor data may be computed for each data point of the stored data. Tolerance factor data may also be computed for each of the utilities in toto. Ground truth data may be used to enhance the accuracy of utility mapping.
A 2-D map or a 3-D map of the utilities may be generated. Mapping data may be incorporated within a Geographic Information System or other positional reference system. The Geographic Information System, for example, preferably defines subsurface mapping data in three dimensions using subsurface depth data. Data associated with one or more of the sensed physical parameters, one or more of the detected utilities, or a map of the detected utilities may be displayed.
In accordance with yet another embodiment of the present invention, an apparatus for detecting underground utilities includes a sensor system comprising a number of sensors. Each of the sensors senses a physical parameter of the subsurface differing from that sensed by other sensors of the sensor system, it being understood that redundant sensors sensing the same physical parameter or parameters may be employed.
A memory stores sensor data acquired by the sensors. A processor is coupled to the sensor unit and memory. The processor controls contemporaneous acquisition of the sensor data from the sensors and detects underground utilities within the subsurface using the sensor data. The apparatus may further include a positional reference system. The positional reference system produces position data associated with a position of each of the sensors.
In one system deployment, the system includes a radar unit that generates radar waves and a seismic unit that generates seismic waves. Preferably, the radar and seismic waves have about the same wavelength, as discussed above. The seismic unit preferably generates seismic shear waves.
The sensor system may include two or more of a ground penetrating radar (GPR) sensor, a seismic sensor, a nuclear magnetic resonance (NMR) sensor, an electromagnetic (EM) sensor, a time-domain electromagnetic (TDEM) sensor, and cone penetrometer instrument. The sensor system may also include one or more of a resistivity sensor, a permittivity sensor, a conductivity sensor, and a magnetometer. One or both of an infrared sensor and a video device may further be included.
The processor, in one embodiment, is coupled to a data fusion engine for processing the contemporaneously acquired sensor data. The processor performs joint inversion of the sensor data to determine a depth and a location of the detected utilities. The processor computes tolerance factor data associated with sensor data stored in memory. The processor weights the stored data using the tolerance factor data. Tolerance factor data may be computed for each of the detected utilities. The memory may store ground truth data and the processor may process the ground truth data to enhance accuracy of utility detection.
A processor, which may be a processor different from that coupled to the sensor unit, generates a map of the detected utilities using the sensor data. Data associated with the map may be incorporated within a Geographic Information System or other geographic reference model. The processor may generate a 2-D map or a 3-D map of the detected utilities. A display is coupled to the processor. The processor causes the display to display data associated with one or more of the sensed physical parameters or one or more of the detected utilities.
According to another embodiment, a utility mapping database system stores, manages, and disseminates utility detection and mapping data. Detector data acquired and processed during a mapping operation is preferably stored in a utility location database. It is understood that data stored and processed within the utility mapping database according to this embodiment may be developed by multiple utility detectors, as discussed above, or a single utility detector, such as a GPR or seismic sensor. As such, the features and advantages realized by implementation and use of a utility mapping database system according to this embodiment of the present invention do not require that the utility data be obtained using a multiplicity of utility detectors.
The utility location database may be a single or distributed database. The utility location database preferably stores mapping data for numerous areas or regions within cities, countries, and continents. The mapping data for given locations may vary in terms of confidence level (e.g., accuracy or reliability), with lower confidence level mapping data being replaced with higher confidence level mapping data over time.
A mapping data distribution system provides user access to mapping data and ancillary resources which may be accessed via public and private interfaces. In one embodiment, internet/web access to the mapping data distribution system provides for world-wide access to the system""s mapping data and resources. Accounting and billing mechanisms provide a means for charging users for accessing and utilizing data and resources of the mapping data distribution system.
The above summary of the present invention is not intended to describe each embodiment or every implementation of the present invention. Advantages and attainments, together with a more complete understanding of the invention, will become apparent and appreciated by referring to the following detailed description and claims taken in conjunction with the accompanying drawings.